Amplifiers are used in a variety of different applications. Depending on the requirement, there are different approaches to implement amplifiers in a circuit. Depending on the amplification behavior, amplifiers can be divided into several classes. For a so-called class AB amplifier, a requirement often to be considered is to provide an output current higher than a bias current while at the same time avoiding possible oscillations due to a large input signal. That problem occurs due to the fact that output currents quite larger than the respective bias current also increase the transconductance of the amplifier stage. To avoid oscillations generated by large input signals, it may be necessary to keep the transconductance of the amplifier stage small enough in any operating condition.
Although several solutions have been proposed in the art using class AB amplifiers or quasi-class AB amplifiers, there is still a need for an amplifier with improved characteristics.